I had a great summer this year doing overnight bivy trips. You get so much riding in when you leave home midday Saturday, ride until 8pm, camp, then ride home again early next morning. 16hrs of Z2 yet only away from the family for Saturday afternoon and Sunday morning.
A trip like this every third week or so plus a couple of more normal long rides in between and I stayed fit as a fiddle all summer long.
When the prospect of a couple of cx races came up in September, I switched to 3 short, fast cx rides a week for only 2 weeks, then raced. I was pretty well as good as I’d ever been and had so much enthusiasm to throw at the race. Was in second place on race 2 until I messed up twice in one lap. Fought back hard but ended up 4th. It was brilliant.
So this is how I’m approaching the rest of the winter. Lots of bike riding; 80km yesterday, inc loads of off road then 3hrs mtb trail riding today (Surrey hills for you UK readers). Lots of work, lots of fun